Conventional methods for protecting surfaces of top coats formed as finish coatings on the surfaces of vehicles include coating thinly with paraffin wax. However, this method involves a problem that it does not exhibit sufficient protecting function and it costs much time and labor when the paraffin wax coating is to be removed, in addition that the effluent, which occurs at the time of the removal, causes environmental pollution, etc.
Meanwhile, there is a method for applying directly a pressure-sensitive adhesive sheet for surface protection to surfaces of coats, such as shown in Japanese Provisional Patent Publication Nos. 73352/1994 and 3420/1997, and however, these adhesive sheets are poor in adhesive property, particularly at low temperature, to coats having hardly adhesive property which is excellent in water repellency and stain resistance, and, since the tear strength and the tensile elongation are small, it has problems that the surface protective adhesive sheets have entirely peeled off at the time of wheels transport in winter season or it has partially peeled because of partial tear or cut.
On the other hand, as a pressure-sensitive adhesive sheet for protecting coats which has good low-temperature properties, proposed is a pressure-sensitive adhesive sheet for surface protection having an adhesive layer in which the main component is a hydrogenated random copolymer of styrene and diene series hydrocarbon (Japanese Provisional Patent Publication No. 149631/1994). Further, proposed is a pressure-sensitive adhesive sheet for protecting coats in which an adhesive containing as main component at least one of a polyisobutylene, a butyl rubber and a polybutene has been applied on a substrate (Japanese Provisional Patent Publication No. 143829/1996). However, although such sheets never peel at the time of wheels transport, there are problems that they are easily cut or torn because of high removal strength at the time of high-speed removal. Alternatively, since it must be removed at low-speed, there are problems that it makes the removal workability worse and it has left stains on surfaces of coats through the influence of tackifier.
The purpose of the present invention is to provide a pressure-sensitive adhesive sheet for surface protection which exhibits good applicability to adhesive-retarded coats having high water repellency and stain resistance, which never peels due to partial tear or cut even at low temperature, which is excellent in protection properties within a broad temperature range, and also which can be easily removed at high-speed without tear or cut at the time of removing.
Further, the purpose of the invention is to provide an adhesive for a pressure-sensitive adhesive sheet for surface protection at low temperature, which is excellent in adhesive property, particularly at low temperature, to adhesive-retarded coats having high water repellency and stain resistance, and which can easily be removed at high-speed without contaminating surfaces of adherends or leaving stains thereon at the time of the removal.